Gao Yuxin, Liu Hang, Wang Xintian, Liu Xiao, Shan Bin, Chen Rong
State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, P. R. China.
State Key Laboratory of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, P. R. China.
Small. 2024 Dec;20(49):e2405748. doi: 10.1002/smll.202405748. Epub 2024 Sep 9.
Pt-based alloy with high mass activity and durability is highly desired for proton exchange membrane fuel cells, yet a great challenge remains due to the high mass transport resistance near catalysts with lowering Pt loading. Herein, an extensible approach employing atomic layer deposition to accurately introduce a gas-phase metal precursor into platinum nanoparticles (NPs) pre-filled mesoporous channels is reported, achieved by controlling both the deposition site and quantity. Following the spatially confined alloying treatment, the prepared PtSn alloy catalyst within mesopores demonstrates a small size and homogeneous distribution (2.10 ± 0.53 nm). The membrane electrode assembly with mesoporous carbon-supported PtSn alloy catalyst achieves a high initial mass activity of 0.85 A at 0.9 V, which is attributed to the smallest local oxygen transport resistance (3.68 S m) ever reported. The mass activity of the catalyst only decreases by 11% after 30000 cycles of accelerated durability test, representing superior full-cell durability among the reported Pt-based alloy catalysts. The enhanced activity and durability are attributed to the decreased adsorption energy of oxygen intermediates on Pt surface and the strong electronic interaction between Pt and Sn inhibiting Pt dissolution.
具有高质量活性和耐久性的铂基合金对于质子交换膜燃料电池来说是非常需要的，但由于在降低铂负载量的催化剂附近存在高传质阻力，仍然是一个巨大的挑战。在此，报道了一种可扩展的方法，即采用原子层沉积将气相金属前驱体精确引入预先填充有介孔通道的铂纳米颗粒（NPs）中，这是通过控制沉积位点和数量来实现的。经过空间受限的合金化处理后，在介孔内制备的PtSn合金催化剂显示出小尺寸和均匀分布（2.10±0.53nm）。具有介孔碳负载PtSn合金催化剂的膜电极组件在0.9V时实现了0.85A的高初始质量活性，这归因于有史以来报道的最小的局部氧传输阻力（3.68S m）。在30000次加速耐久性测试循环后，催化剂的质量活性仅下降了11%，在已报道的铂基合金催化剂中表现出卓越的全电池耐久性。活性和耐久性的提高归因于氧中间体在铂表面的吸附能降低以及铂和锡之间强烈的电子相互作用抑制了铂的溶解。
